The present invention relates to optical fiber splices, and more particularly to the protection of a fiber splice from degradation due to the surrounding environment and physical stress.
A typical optical fiber is fabricated as a thin filament of silica-based material with a core region of one refractive index and a peripheral cladding of a lesser index. A jacket, typically of a strong flexible plastic having a thickness several times that of the filament, is generally provided to add strength and to protect the fiber from physical and chemical damage. When two or more such fibers are to be spliced end-to-end, the jacket is first removed from a portion of each fiber and the bare fiber ends are then spliced. The splice region therefore remains unprotected, and may be subjected to localized stresses from physical contact. It is also vulnerable to absorbing atmospheric vapors which can alter the fiber characteristics and degrade its performance.
In order to achieve a splice which does not absorb material from the environment or is not subject to undue physical stresses at the junction region, it is customary to cover the fiber junction with a support structure and to fill the support with a potting medium. See, for example, U.S. Pat. No. 4,593,968 of Giallorenzi.
Such structures, however, are cumbersome, and fibers spliced in this manner do not lend themselves to the flexible packaging constraints often required of fiber optic instrumentation. Moreover, the provision of a splice-protecting structure can require special mounts and may itself introduce unwanted stresses in the fiber. Further, such structures require a cumbersome fabrication process.